This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This project investigates the tolerance of unique microbes to acidic environments such as that found in the stomach. The acid tolerance response (ATR) of these microbes appears to involve a sequence of events that both includes and surpasses that which is normally seen in common pathogens. In addition to the normally expected stress response, there appears to be a significant change in metabolic pathways